NEUROLOGICAL METHODS. 393 



Monatsschr., xv, 1898, H. 8; AUERBACH, Monatsschr. Psychiatric, iv, 1898, 

 p. 31 ; Zeit.f. wiss. Mik., xv, 1899, p. 493; BUEHLER, Verh. Phys.-Med. 

 Ges. Wiirzburg, xxxi, 1898, p. 285 ; Zeit.f. wiss. Mik., xv, 1899, p. 351. 



(b) Nerve Fibres. 



703. Structure of Medullated Nerve. In order to demon- 

 strate the axis- cylinder and the sheath of Schwann, the 

 myelin may be removed. This may be done by boiling in 

 caustic soda, and then neutralising ; by boiling in a mixture 

 of absolute alcohol and ether, and adding caustic soda ; by 

 boiling in glacial acetic acid; by boiling in fuming nitric 

 acid, and adding caustic potash ; or by treating with eau de 

 Javelle ; or (VAN GEHDCHTEN, in litt.) the myelin may be 

 extracted in the cold by leaving the nerves for some time in 

 a mixture of alcohol and ether. 



704. Axis-Cylinder, KUPFFEK'S Method (Sitzb. math. phys. 

 Kl. If. Bayr. Akad. Wiss., xiii, 1884, p. 470 ; Z&it. f. wiss. Mik., 

 1885, p. 106). A nerve is stretched on a cork and treated 

 for twenty-four hours with O5 per cent, osmic acid. It is 

 then washed in water for two hours and stained for twenty- 

 four to twenty- eight hours in saturated aqueous solution of 

 Saurefuchsin ; after which it is washed out for from six to 

 twelve hours (not more in any case) in absolute alcohol, 

 cleared in clove oil, imbedded in paraffin, and cut. 



Iron haematoxylin sometimes gives a sharp stain of axis- 

 cylinders. 



See also the complicated method of AUERBACH, Neurol. Centralb., 1897, 

 p. 439 ; Zeit.f.^wiss. Mik., xiv, 1897, p. 402. 



705. Formol-Methylen-Blue. ROSSOLIMOW and MUUAWIEW 

 (Neurol. Centralb., xvi, 1897, p. 722; Zeit.f. wiss. Mik., xiv, 

 1898, p. 511) harden pieces of nerve in 2 per cent, formol 

 solution for two days, then for two more in 4 per cent., 

 tease or section, stain in warmed methylen blue, with heat, 

 and differentiate with anilin alcohol, as in Nissl's process, 

 clear in oil of cajeput, and mount in balsam. 



706. Neuroceratin Structures (&ALLI, Zeit.f. wiss. Mik., iii, 1, 1886, 

 p. 467). Small portions of ischiatic nerve are treated for one or two days 



